1. Field of the Invention
The present invention relates to a flat illumination light which can be applied to, for example, an ordinary illumination light, a backlight for a liquid crystal display (LCD) or the like.
2. Description of the Related Art
Known illumination lights include a fluorescent lamp for domestic use, an electroluminescence (EL) for a backlight in a liquid crystal display or the like, and so on. A display apparatus utilizing a plasma discharge is also known.
FIGS. 1 and 2 are diagrams showing a plasma display apparatus by way of example. A plasma display apparatus 1 is formed of a transparent substrate, e.g., a glass substrate 4, having on its inner surface a plurality of stripe electrodes, i.e., anodes 2 and cathodes 3 made of transparent electrodes which are alternately arranged, and of a rear substrate 7 having on its inner surface a plurality of stripe address electrodes 5 and a fluorescent layer 6 extended in a direction perpendicular to the anodes 2 and cathodes 3.
Both substrates 4 and 7 are arranged opposite each other with a surface of the glass substrate 4, on the side of the anodes 2 and cathodes 3, and a surface of the rear substrate 7, on the side of the address electrodes 5 and the fluorescent layer 6, being disposed to face inward. Both of the substrates 4 and 7 form a sealed vessel 10 shielded in an airtight manner through a peripheral spacer 9.
In the sealed vessel 10, stripe barrier walls 11 perpendicular to the anodes 2 and cathodes 3 are provided so that each of the stripe barrier walls 11 is located between the adjacent address electrodes 5. The barrier walls 11 section the address electrodes 5 and the fluorescent layer 6.
In the plasma display apparatus 1, when a discharge maintaining voltage is applied between the anode 2 and the cathode 3 and then a discharge start voltage is applied between, for example, the cathode 3 and the address electrode 5, discharge between the corresponding anode 2 and the corresponding cathode 3 is produced. This discharge produces a plasma 13, and the fluorescent layer 6 is excited by ultraviolet rays 14 from the plasma 13 and emits light to carry out a desired display.
An interval between electrodes, i.e., an interval between the anode 2 and the cathode 3 in the above plasma display apparatus 1 is usually set within the range substantially from 100 .mu.m to 200 .mu.m.
In case of the illumination light, a fluorescent light has a cylindrical shape and hence has a considerable volume, making it difficult to reduce the size of the fluorescent light significantly. An electroluminescence (EL) tends not to deliver sufficient brightness or a desirable tone. Conventional plasma display apparatuses also tend to have brightness deficiencies.